Technology and media change rapidly in recent years. Applying new technical tools may cause privacy concerns, leading to a low willingness to disclose personal information. Information disclosure is an important factor to facilitate the development of a new technology, which often decreases while a user's privacy concern increases. Technical tools have to reduce user uncertainty through rich information provided. Media richness theory has been discussed in different media platforms for a while. Also, task technology fit (TTF) has been applied to various information systems across diverse task contexts. To examine the relationship between privacy concerns, information disclosure, media richness, and information technologies, the media richness theory was extended with the TTF concept in this study. Six participants were recruited to the study, where technology platforms (iPad vs. Pepper robot) and unmanned store service were included in the experimental design. The findings show that privacy concern has a negative impact on information disclosure. Additionally, the service context also significantly influences information disclosure.